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R, which sums, not frequency

I am new to using R and I am trying to create a histogram where the axis shows the sum of another bar, not just the frequency.

Example
I have a matrix with two columns, RATE and BALANCE. I would like to create a bar chart that shows the amount of the balance, not just the number of entries.

hist(mydata$RATE)

# only shows the frequency. How can I get the amountmydata$BALANCE

I would like to create a bar chart that summarizes the BALANCE column rather than just making a count of entries. something like hist(mydata$RATE, mydata$BALANCE)

, but obviously the hist function doesn't take a sum parameter

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2 answers


It looks like you are trying to build a bar. The corresponding function barplot

can help.

First, as suggested by @DWin, create some reproducible data :

set.seed(1) # Sets the starting seed for pseudo-random number generation
mydata <- data.frame(RATE = sample(LETTERS[1:5], 100, replace = TRUE),
  BALANCE = rpois(100, 15) * 10)

Then create summary data using the function tapply

. This will calculate the sum of your variable BALANCE

over each value of your variable RATE

.



plotdata <- tapply(mydata$BALANCE, mydata$RATE, FUN = sum)

Then sketch using barplot

:

barplot(plotdata)

enter image description here

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This is not an example we can test to make sure it meets your expectations (nor is it clear what you mean by "taking the sum parameter"), but try this:



hist( cumsum( mydata$BALANCE) )
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